I've seen all their tricks; the most common one, when their dog has done what dogs do best, is to furtively look around to see if there happens to be an observer: if negative, they'll pretend they haven't seen the mess (which is why the the dog is off-lead anyway??) and leave it there, and if the obscene deed might have been witnessed, the owner grudgingly puts the unspeakable into a plastic bag . . . then chucks it over a hedge into someone's garden asap. Typically they're anti-social, lazy, and thoroughly irresponsible; and if you don't show any interest in their four-legged obsession(s), they'll hate you for ever. I quoted the wrong post in the previous version and it's too late now to delete it. Soz about that.